Superheating system for fire-tube boilers



June 24, 1930.

P. THOMSEN SUPERHEATING SYSTEM FORFIRE TUBE BOILERS Filed Jari. 22, 19272 Sheets-Sheetl l duerma .une 24; 1930. P. THOMSEN 1,768,169

SUPERHEATING SYSTEM FOR FIRE TUBE BOILRS Filed Jan. 2T?, 1927 2SheetS-Sheet 2 20 I 10 ZL 18 20 w," @MPb Patented June 24, 1930 'UNIT-rar :PETER THOMSEN, 'DECEASED, LATE OF CASSEL, GrERMiLNY,` BY REINOLDKRUM MACHER, ADMINISTRATOR, `OF CASSEL, GER-M'ANY, ASSGNOR TOSGHMDTSCI-IE 'HEISSDAMPF-GESELLSCHAFT MIT BESCHRNKTEE HAFTUNG, OF iCASSEL-NL- HELMSHOHE,GERMANY, ACORPORATION-OF GERMANY lVstimaRIYIEA'rINGsY'sTnivi non MRE-TUBE Bomans Application'ledJanuary22, 1927,` Serial No. 162,873, and in Germany January 23, 1926.

This invention relatesV to a superheating systemffor fire-tubeboilers.andy-has for its object to provide 1 an efficient apparatus whereby thesteam may be heated to higher temperatures than have; previously beenpracticable in commercial boilers'.V

The known type of superheater, wherein the steam is passed throughU-loops disposed in the fire tubes of the boiler, is not effective toheat the steam above about 330 C., sinc.I the combustion gases, intraversing the fire tubes, transmit too much heat to the boiler waterbecause of the large surface of the fire-tubes in contact with thewater. If, on the other hand, a superheater of the so-called furnaceflue type is used, in which all the superheater elements are locatedtogetherin only one large lfire tube or chamber or in a few large firetubes, a higher temperature may be attained. In this case, however, theboilers evaporating surface in contact with the water becomes too smalland thefire gases are not utilized favourably enough.

The present invent-ion is designed to provide means whereby the steammay be superheated to 375 to 400 C. while doing away with thesedisadvantages. To this end, the vsuperheater -comprlsestwo stages, thefirst stage consisting of a lire-tube superheater7 the pipes of whichare disposed in Va pluralvity of fire tubes of the boiler, the secondstage consisting of a furnace flue superheater the pipes of which arelocated in vone or more comparatively large pipesor tubular chambers,the two stages being connected Vin f' series. In lthe first stage thesteam is superheated to a certain degree and in the second stage thesteam isi-raised to the desired high temperature. The second stage 1spreferably disposed in such a manner with'respect to the elementsand theheader ofthe first stage superheater, that the pipes of the. respectivestages may be mounted and taken outl without interfering with eachother.

While the provisionof the second-stage superheater necessarily somewhatreduces the heat`-absorbing or evaporating surface of the boiler, yetthe second stage of the superheater having a greater and more efhcient50 rheating surface as compared with the lire Vposed between tubefirststage superlieater, the whole arrangement is very efficient where it isdesired to superheat steam to a high' temperature. I The invention isillustrated in the accompanying drawing as applied to a cylindricalmarine boiler, but it may be used with other types of boilers. i

Fig. `1 is a view of the front end of a niarine boiler with parts'brokenaway, showing a preferred embodiment of the invention; Fig. 2 is asectional viewtalren on 2,-42 of Fig.v l, and

Fig. 3 is a sectional view takeny on the line 3 3 of Fig. 1L f YThemarine boiler shown in the drawing haslire tubes 6 and cylindricalchambers 7 extending the length of the boiler to permit the combustiongases to'pass from the vrear Oftheboiler to the smoke box 8 and throughthe air-preheater tubes 8f to the stack 9.

Steam pipe 10 conducts the steainfroin the boiler to a wet-steam chamber11V at 'the' center of the smoke box. Leads 12feXtend laterally fromchamber. 11 to U-loops 13, po-

sitioned in the fire tubes 6, and'leads 14 conduct theV steam from theU-loops back toV av `second steam chamber 15 the steam attaining acertain degree'ofsuperheat during its u passage ythrough loops 13 whichconstitute the first stage Vof the superheater. f From chamber 15 thesteam is conducted by pipes 16 to the headers 17. ofthe second *Y stage.A number of parallel 'steam coils 18 extend from headers 17, into thechambers 7V and back to otherheaders 19,' whencethe Vsteam is conductedby pipes 2O `to theengiiies.l Connecting chambers 2l are` inter- 17 and19.

Due to the comparatively large diameter of chambers 7, thegases-whicli-come in contact with coils 18 are hotter than those passingthrough the fire tubes 6; hence the steam in passing through the secondstage is raised to ay much higherl .temperature thanjis reached in thefirst stage of the superheater.v i

superheaterfof the illustrated embodiment is arranged so.v that (atleast in the lower The, lire tubesuperheater (the primary y the unesteam coils 18 and-fV headers Y portion of the boiler) ineach horizontalrow of fire tubes there are disposed four elements each located in threefire'tubes. In the upper portion of the boiler the arrangement ismodified so that some of the elements are disposed in two ktire tubesonly.

' The second-stage superheater (the secondary superheater) comprises .anumber ofcoiled elements arranged in the ilues or chainbers .7inparallel planes.` ln each plane preferably tivo (as shown? inthedrawings) or more coils are disposed the ends of which are Yconnectedtothe ,connectingY chambers 21 removably secured to the headers 17 Vand19.

rlhe chambers? preferably are arranged in tlieupper portion el the liretube area o'l the boiler-and on that sideorn the boiler Where Vtheheader of the lire tube (first stage) superheater is not situated.rllhus in the exampleV illustrated the tubes or 'chambers 7 are locatedeach on one side of saidfire tube area of the boiler Whereasthe hea-dersVAil and 15 aredisposed in ytrent of the middleV portion of the boiler.Y'lfhus the elements of the dif?V ferent superheaterswill notinterferewith each other. 'i .Y i

v/*hat is claimedis v l. A superheater for a tire tube boiler,compi'ising besides the lire tubes a tube or chamber of largecross-section extending length- Wise of the boiler and adapted toconduct combustion gases, saidsuperheater comprising a first stagedisposed iii the lire tubes ofl the boiler, andaseccnd stage disposed insaid tube .or chamber and connected inseries With VVVsaid first stageYto receivesteam therefrom.

12. A superheater for a fire tubeboiler, com- Y prising a plurality etelements disposed in the lire tubes ci. the boiler-headers `lier. saidelements, a cylindrical chamber' extending through 'the boiler yandadapted to conductcombustion gases, a plurality o elements dispesed insaidchamber and .connected iii series with said l'lirstlmentionedelements to receive steam therefrom, headers''or said second mentionedelements, said iirstmen tioned elements bein;ovv ada ited to be mountedand to be taken j s 7;. n y out Without interfering With said secondmentioned elements.

Vclaim 2, in which the second mentioned ele- 3. A- superlieating systemasv deined iii elements to receive steam therefrom,and a header for saidsecond mentioned elements,`

said chamber being arranged on a sideof the boiler opposite to saidfirst mentionedlr r i header. Y Y

5. A superheater for a re tube boiler, com.-

prising a chamber receiving Wet steam fromY the boiler,..a pluralityAinf heat exchange ele- .ments arranged `to conduct steam from saidchamber throiigh'thetire tubes, yan enlarged chamber extending throughthe boiler and adapted to conduct combustionvgases, heat exchangeelementsdisposed in said chamber and connectedin .series with saidlfirst inentioned elements to receive v'steam therefrom, said firstmentioned heat exchange elements and said second mentioned heat exchangeelementsbeing adapte-d to be mountedY and .re. p

moved independently of each other. v

REINOLD KRUMMACHER,

' Administrator of Peter Thomsen, Deceased.

mentsconsist of Va series of coils disposed in 'A combustion gases, aplurality 'of element-s dis- Y posed in said chamber in parallel planesand 'connected Vin series With said first mentioned l Y y extend-ingvthrou the boiler and adapted to conduct

